Accessing Environment And System Variables On Windows 7

This is a reminder describing how to access environment and system (including path) variables under Window 7:

1. Open Windows Explorer.
2. On the left part of the screen, select the Computer icon.
3. Right-click this icon and select properties.
4. A window will open, select Advanced System Settings.
5. A System Properties windows will open.
6. At the bottom, click Environment Variables.

About Using System.Exit() in Try Catch Finally Java Statements

This post is an attempt at summarizing issues around using the Java system.exit() statements inside try {...} catch (...) {...} finally {...} statements.

We will use the following piece of code:

public class TryCatchFinallySystemExit {

  public static void main(String[] args) {

    System.setSecurityManager(new SecurityManager() {

      @Override
      public void checkPermission(Permission perm) { }

      @Override
      public void checkExit(int status) {
        // throw new SecurityException();
      }

    });

    System.out.println("Before Check");
    check();
    System.out.println("After Check");

  }

  public static void check() {

    try {

      System.out.println("Before System.exit(-1)");
      System.exit(-1);
      System.out.println("After System.exit(-1)");

    } catch(Throwable t) {

      System.out.println("Before System.exit(-2)");
      System.exit(-2);
      System.out.println("After System.exit(-2)");

    } finally {

      System.out.println("Before System.exit(-3)");
      System.exit(-3);
      System.out.println("After System.exit(-3)");

    }

    System.out.println("After try statement");

  }

}

The main method implements a SecurityManager, then calls the check() method. If we run this application as is, the output is the following:

Before Check
Before System.exit(-1)

We can conclude that:

• System.exit(-1) is the last statement excuted.
• Catch and Finally statements are not called.
• The check() method does not return.

If we uncomment the throw new SecurityException(); and execute the application again, we get:

Before Check
Before System.exit(-1)
Before System.exit(-2)
Before System.exit(-3)

We can conclude that:

• The SecurityException get the catch and finally statements to be executed.
  
• Statements after System.exit() statements are not executed.
• The check() method does not return.

For return, continue and break statements in try statements, see this post.

Disclaimer: this post contains information from personal notes and information available on StackOverflow.com.